I am preparing to tow my 500L Trecking behind my motorhome. I want to use Roadmasters wiring kit with bulbs that are added to the stock units. This makes it possible to have lights without tapping in to the cars electrical system. My problem is I can't figure out how to remove the taillights to place the bulbs.
Can anyone out there help me?

Hi, and welcome to FF,
I 'm not too familiar with the 500L,

but FIAT often use a "BOLT / STUD" from the light cluster,
passing into the passenger compartment( with a NUT on the end to secure it.., )
the nut is often under a small access panel in the plastic trim,

do you have an owners manual ?,
changing a bulb is usually covered..,
look here to download a manual.. see exploded views of components;

http://eper.fiatforum.com/

https://www.fiatforum.com/downloads.php?do=cat&id=2

good luck,
Charlie